Electrophysiological Testing

Electrophysiologic—assesses neural processes in the central auditory pathway and provides information about the integrity of the CANS from the vestibulocochlear nerve (also known as the "auditory vestibular nerve" or "eighth cranial nerve") to the auditory cortex. These measures include auditory brainstem response (ABR), middle latency response (MLR), late cortical response, P300, and mismatch negativity.

Electrophysiologic measures may be useful in cases where behavioral procedures are not feasible (e.g., infants and very young children, non-English speakers), when there is suspicion of frank neurologic disorder, when a confirmation of behavioral findings is needed, or when behavioral findings are inconclusive.

About the ABR

Your ear is made up of three parts—the outer, the middle, and the inner ear. The auditory brainstem response (ABR) test tells us how the inner ear, called the cochlea, and the brain pathways for hearing are working. You may also hear it called an auditory evoked potential (AEP).

The test is used with children or others who cannot complete a typical hearing screening. The ABR is also used if your symptoms might be due to hearing loss in the brain or in a brain pathway.

How the ABR Is Done

You will have electrodes put on your head to get ready for the ABR. The electrodes are stuck to your skin and connected to a computer. They record brain wave activity in response to sounds you hear through earphones. All you have to do is rest quietly or sleep during the test. You do not have to say or do anything. The person doing the test will see the results on a computer printout.

ABR for Babies

ABR can also be used as a screening test in newborn hearing screening programs . A screening is a test where you either pass or fail. When the ABR is used for screening, only one loudness level is checked. The baby passes if his brain shows that it is hearing the sound. If the baby fails the test, more specific testing will be done.